Fractionation method for sucrose-containing solutions

ABSTRACT

A method for separating sucrose and a second dissolved component from a sucrose-containing solution, preferably a beet-derived sucrose-containing solution, wherein the solution is subjected to a first fractionation by a continuous or sequential chromatographic simulated moving bed process to yield a sucrose-enriched fraction and a fraction enriched with the second dissolved component. The resulting fraction enriched with the second component is subjected to a second chromatographic fractionation that is a simulated moving bed or batch type process, to yield a second sucrose-enriched fraction and a second fraction enriched with the second dissolved component wherein both fractions have an improved yield or purity.

This application is a continuation of prior application Ser. No.08/486,921, filed Jun. 7, 1995, now U.S. Pat. No. 5,795,398.

FIELD OF INVENTION

The present invention relates to a method for separating sucrose and,optionally, a second dissolved component from solution. Moreparticularly, the invention relates to a method in which a solutioncontaining sucrose and other dissolved substances is first fractionatedby a chromatographic simulated moving bed (SMB) process to yield asucrose-enriched fraction and, optionally, a separate fraction enrichedwith a second component to be recovered. When two separate fractions areproduced, the latter fraction is further fractionatedchromatographically, either by a batch method or a simulated moving bedmethod. In a preferred embodiment, a beet-derived sucrose-containingsolution is fractionated to yield a sucrose-enriched fraction and afraction enriched with a second orcanic compound commonly present inbeet-derived solutions, such as betaine, inositol, raffinose,galactinol, or serine and other amino acids.

BACKGROUND OF THE INVENTION

It is known that sucrose and betaine are recoverable from molasses bychromatographic separation. U.S. Pat. No. 4,359,430 to Suomen Sokeri Oy,describes a chromatographic method for the recovery of betaine frommolasses by a batch process in which diluted molasses is fractionatedwith a polystyrene sulphonate cation exchange resin in alkali metalform. This method achieves good separation of sucrose and betaine. Thisreference also discloses a method in which a betaine-enriched fractionobtained from a first fractionation is subjected to furtherchromatographic purification. The further purification step is said tobe capable of separating other components from the betaine-enrichedfraction. However, the dry solids content in the sucrose and betainefractions obtained by this method is relatively low, therefore, largeamounts of eluant water must be evaporated when recovering the sucroseand betaine from the respective fractions by crystallization.

Continuously operated chromatographic separation processes presentlyemploy the SMB method, which method is used in a variety of differentapplications. The SMB method has a separating performance that isseveral times higher than that of the batch method, and also results insignificantly lower dilution of the products or, conversely, lowerconsumption of eluant.

The SMB method may be carried out in either a continuous or a sequentialmode. In both processes, the pattern of fluid streams is the same. Thesestreams are (1) the supply of feed solution and eluant to the bed orbeds, (2) the recycling of the liquid mixture between beds, and (3) thewithdrawal of products from the beds. The flow rate for these flows maybe adjusted in accordance with the separation goals, i.e., increasedyield, purity, or capacity. In a continuous SMB process, which was firstdisclosed in the early 1960s in U.S. Pat. No. 2,985,589, all fluidstreams flow continuously. Separation of sucrose by such continuous SMBmethods has been described in international publication no. WO 91/08815by the Amalgamated Sugar Company and in U.S. Patent 4,990,259 to M.Kearney and M. Mumm and assigned to The Amalgamated Sugar Company.

In a sequential SMB process, some of the fluid streams do not flowcontinuously. Sequential SMB fractionation methods in which a sucrosefraction and a betaine fraction are recovered from beet molasses aredisclosed in Finnish Patent 86,416 to Suomen Sokeri Oy, whichcorresponds to U.S. Pat. No. 5,127,957 and international publication no.WO 94/17213 to Suomen Sokeri Oy. German Offenlegungsschrift 4,041,414 toJapan Organo Co., which corresponds to British published application2,240,053, also discloses a sequential SMB method by which severalproduct fractions are recovered from sugarbeet molasses.

In the sugar industry, the important parameters in the fractionation ofmolasses to recover sucrose include the purity and yield of sugar, theseparation capacity, and the eluant/feed ratio. A purity of 92% and ayield of 90% are the usual requirements for a sugar product. In order toincrease the capacity to recover sugar from the process, the flow rates,which are generally higher in SMB processes than in batch processes, areincreased. Along with the increase in the flow rate, however, a “flattail” is produced in the sucrose elution profile. A “flat tail” meansthat the concentration of sugar has not peaked sharply, but, rather, hasbeen considerably diluted with the increased volume of eluent. This isespecially disadvantageous to the recovery of a second dissolvedcomponent. With respect of the recovery of sucrose and betaine, thiseffect is shown in the elution profiles presented in U.S. Pat. No.4,359,430 and Finnish Patent 86,416, for example. In the course ofobtaining a high sucrose yield, the betaine yield is diminished becausepart of the betaine is allowed to pass into the sucrose fractionwherefrom it is removed in the sucrose crystallization step. Likewise,if a high betaine yield is desired, considerable amounts of sucrose endup in the betaine fraction, thus diminishing the sucrose yield andconsiderably impairing the purity of the betaine fraction.

In the above references, the purity of the betaine fraction obtained bythe process of German Offenlegungsschrift 4,041,414 is relatively good,80.9% on a dry solids basis (d.s.), but the purity of the sucrosefraction, 87% d.s., is inadequate for the sugar industry. It can beconcluded from the composition of the feed solution of Example 3 in thereference that the “thin juice” was demineralized prior to the SMBfractionation by the “KAAK method” (which refers to cationexchange-anion exchange-anion exchange-cation exchange as described inSayama, K., Kamada, T., and Oikawa, S., Production of Raffinose: A NewBy-Product of the Beet Sugar Industry, British Sugar plc, TechnicalConference, Eastbourne 1992). Molasses produced by such a beet sugarprocess has a different composition from common molasses. Typically,beet molasses contains 1.5-3.50 by weight of raffinose and 3.5-6.5weight % of betaine on a dry solids basis. Since the feed solution ofExample 3 in German Offenlegungsschrift 4,041,414 has a raffinosecontent of 17.3% by weight and a betaine content of 12.26 by weight on adry solids basis, it can be concluded, on the basis of theraffinose-to-betaine ratio, that roughly half of the betaine containedin common beet molasses was lost in the ion exchange treatment.

According to Finnish Patent 86,416, a purity as high as 70.9% d.s. forthe betaine fraction was obtained, with 11.1% d.s. of sucrose present inthe betaine-enriched fraction. However, the 86.8 a purity of the sucrosefraction does not meet the requirements of the sugar industry.Similarly, the 47.5% purity of the betaine fraction reported ininternational publication no. WO 94/17213 is rather poor.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the present invention to fractionate sucrose and asecond desired organic component, such as betaine, inositol, raffinose,galactinol, serine, or other amino acids, from a solution so as toobtain higher yields with at least equivalent purity for sucrose.

It is also an object of the present invention to fractionate sucrose andbetaine from a beet-derived sucrose-containing solution with a higherpurity and a higher yield for betaine.

It is a further object of the present invention to provide an economicalfractionation method, in terms of capacity and the eluant/feed ratio,that separates two components from a sucrose-containing solution withhigh yield and high purity as economically as the prior SMB methods forfractionating sucrose-containing solutions.

Accordingly, the present invention is a method for separating sucroseand, optionally, a second dissolved component from a sucrose-containingsolution, preferably a beet-derived sucrose-containing solution, inwhich the solution is subjected to a first chromatographic fractionationby a SMB method to yield a sucrose-enriched fraction (hereinafter thefirst sucrose fraction) and a fraction enriched with the seconddissolved component, and the resulting fraction enriched with the secondcomponent is subjected to a second chromatographic fractionation, toyield a second sucrose-enriched fraction (hereinafter the secondfraction) and a second fraction enriched with the second dissolvedcomponent. The first fractionation may be carried out so that sucroseand the second dissolved component are enriched in the same fraction, orpreferably, they are enriched in separate fractions.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic diagram of a three-column sequential SMB processas described in Example 1 for separating sucrose and betaine frommolasses;

FIG. 2 is a truncated schematic diagram of a fourteen-column continuousSMB process as described in Example 4;

FIG. 3 is a graph of the concentration gradient of the liquidcirculating in the fourteen-column system shown in FIG. 2 over time;

FIG. 4 is a truncated schematic diagram of a fourteen-column continuousSMB process as described in Example 5;

FIG. 5 is a graph of the concentration gradient of the liquidcirculating in the fourteen-column system shown in FIG. 4 over time;

FIG. 6 is a truncated schematic diagram of a fourteen-column continuousSMB process for separating sucrose and betaine from molasses asdescribed in Example 6;

FIG. 7 is a schematic diagram of a three-column sequential SMB processfor the second fractionation of betaine as described in Example 6; and

FIG. 8 is a graph of the concentration gradient of the liquidcirculating in the fourteen-column system shown in FIG. 6 over time.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a method for separating sucroseand, optionally, a second dissolved component from a sucrose-containingsolution. The solution is subjected to chromatographic fractionation bya continuous or sequential SMB method where the two components areenriched in the same fraction or in separate fractions and either thesingle fraction or the second fraction is subjected to a secondchromatographic fractionation in order to recover sucrose and a secondcomponent with an improved yield or purity.

In accordance with a preferred embodiment of the invention, the secondsucrose fraction is combined with the sucrose fraction from the firstchromatographic fractionation, and sucrose is recovered from thecombined sucrose fraction thus obtained.

In accordance with another preferred embodiment of the invention, thesecond sucrose fraction is returned to the feed solution for the firstfractionation. In this embodiment, sucrose is recovered from the firstsucrose fraction.

Generally, the second dissolved component is recovered from the fractionobtained from the second fractionation, which is enriched with thesecond dissolved component. The term “second dissolved component” refersto organic compounds commonly present in beet-derived solutions, such asbetaine, inositol, raffinose, galactinol, or serine and other aminoacids. The second chromatographic fractionation, i.e., fractionation ofthe fraction enriched with the second dissolved component which isobtained from the first fractionation, may be performed either by abatch method or a SMB method.

The invention is particularly suitable for the recovery of sucrose andbetaine from beet molasses. Therefore, the following description of theinvention specifically refers to the recovery of sucrose and betaine,but the invention is not so limited. Instead of, or in addition tobetaine, any other dissolved organic substance may be similarlyrecovered by adjusting the process conditions and parameters to suit theseparation in question, which can be achieved easily by those skilled inthe art.

With the method of the invention, the sucrose yield can be improved byup to about 10 percent compared with the SMB processes presentlyemployed in the sugar industry. This improvement represents remarkableeconomic advantages in view of the large amount of the molasses used bythe sugar industry for chromatographic separation. For example, in theUnited States, about 500,000 tons d.s. of molasses are currently usedper annum. The purity of the sucrose fraction produced by the method ofthe invention meets or exceeds the goal of about 92% set for industrialSMB methods.

With regard to betaine, the method of the invention can achieve yieldsas high as about 95%, which is a significant advantage over prior yieldsof about 30-70%, and a purity as high as about 95%, calculated on a drysolids basis, which is a substantial increase over purities of about25-70% hitherto obtained.

The first chromatographic separation in the method of the invention maybe carried out with prior art SMB methods and apparatus known to besuitable for the fractionation of molasses, such as those disclosed inU.S. Pat. No. 4,402,832 (continuous SMB method), Finnish Patent 86,416,and international publication no. WO 94/17213 (discussed above).

Also, the further fractionation of the betaine fraction produced in thefirst fractionation to yield a second sucrose fraction and a secondbetaine fraction may be carried out by known chromatographic separationmethods and apparatus, such as the methods and apparatus disclosed inU.S. Pat. No. 4,359,4130 (batch method), and Finnish Patent 86,416 andinternational publication no. WO 94/17213 (SMB methods).

In the continuous SMB method, all flows (supply of feed solution andeluant, recycling of liquid mixture, and withdrawal of productfractions) are typically continuous. The rates for these flows may beadjusted in accordance with the separation goals, namely, yield, purity,and capacity. There are normally 8 to 20 packed beds that are combinedinto a single continuous loop. The feed and product withdrawal pointsare shifted cyclically in the downstream direction in the packed bed.Due to the supply of eluant and feed solution, the withdrawal ofproducts, and the flow through the packed bed, a dry solids profile isformed in the packed bed. Constituents having a relatively low migrationrate in the packed bed are concentrated in the back slope of the drysolids profile, while ingredients having a higher migration rate areconcentrated in the front slope. The points of introduction of the feedsolution and eluant and the withdrawal points of the product or productsare shifted gradually at substantially the same rate at which the drysolids profile moves in the packed bed. The product or products arewithdrawn substantially from the front and back slopes of the dry solidsprofile. The feed solution is introduced substantially at the pointwhere the composition of the cyclically moving dry solids profile isclosest to the composition of the feed solution, and the eluant isintroduced approximately at the point of minimum concentration of thedry solids profile. Part of the separated products are recycled due tothe continuous cyclic flow, and only part of the dry solids is withdrawnfrom the packed bed during one sequence.

The feed and withdrawal points are shifted cyclically by using feed andproduct valves located along the packed bed, typically at the upstreamand downstream end of each section of the packed bed. (The requisitevalves and feed and withdrawal equipment are part of the apparatus). Ifproduct fractions of very high purity are desired, short phase times andmultiple sections of packed beds must be employed.

In the sequential SMB system, not all flows (supply of feed solution andeluant, recycling of liquid mixture, and withdrawal of products) arecontinuous. Yet the shifting of the dry solids profile or profilesmoving cyclically in the system is continuous. The flow rate and thevolumes of the different feeds and product fractions may be adjusted inaccordance with the separation goals, i.e., yield, purity and capacity.During the feeding phase, a feed solution, and, optionally, also aneluant during a simultaneous eluting phase, is introduced intopredetermined packed beds, and, simultaneously, one or more productfractions are withdrawn. During the eluting phase, eluant is introducedinto a predetermined packed bed or beds and, during the feeding andeluting phases, one or more product fractions are withdrawn.

During the recycling phase, essentially no feed solution or eluant issupplied to the packed beds and no products are withdrawn. A forwardflow is maintained in a fixed direction in a system comprising at leasttwo columns, and the products are recovered during a multi-step sequencecomprising the above phases. One column may equal a single packed bed ora portion of a packed bed. In the latter configuration, the columns thatmake up a packed bed are referred to as “sectional packed beds.”

During the feeding phase, feed solution is introduced into a column anda corresponding quantity of any product fraction is withdrawn at a pointwhich may be located either in the same column as the feed point (inwhich case the other columns in the system may be, for example, in theeluting or recycling phase) or in a different column from that of thefeed point, which column is connected in series (optionally throughother columns) with the column into which the feed is introduced. Duringthe recycling phase, the liquid in the columns, along with its drysolids profile or profiles, is recycled in a loop comprising one, two orseveral columns. In the eluting phase, eluant is introduced into thecolumn and a corresponding amount of product fraction(s) is (are)withdrawn from the same or a downstream column.

As stated previously, a detailed description of these sequential SMBprocesses applied to the recovery of sucrose and betaine from beetmolasses is provided in Finnish Patent 86,416 and internationalpublication no. WO 94/17213; these processes may be employed in themethod of the present invention to carry out both the first and thesecond fractionation.

By moving the resin bed in a column into which the feed solution isintroduced counter-currently to the liquid flow direction of the drysolids profile, an actual moving bed system can be achieved. It isself-evident that results very similar to those achieved with asimulated moving bed can be obtained with such an actual moving bed.

In the method of the invention, preferably a gel-type strong cationexchanger (eg., “Dowex”, Finexr or “Purolite”) is employed as thepacking material for the columns, and it is preferably in sodium and/orpotassium form. The packing material is preferably equilibrated to thetonic form of the feed solution prior to the fractionation.

The dry solids content of the beet-derived sucrose-containing solutionto be fed to the chromatographic separation is typically 20-80 g/100 g,preferably 40-70 g/100 g. The solution is heated to 40-95° C.,preferably 65-85° C., prior to being supplied to the separation process.

The elution phase employs mainly water and/or very dilute aqueoussolutions (having a dry solids content less than 8% by weight,preferably less than 1 by weight). The eluant has a temperature of40-95° C., preferably 65-85° C.

The dry solids content of the betaine fraction obtained from the firstfractionation is adjusted prior to the second fractionation to about20-50 g/100 g for batch separation or, typically, to 20-80 g/100 g, andpreferably 40-70 g/100 g, for SMB separation.

Sucrose can be recovered from the sucrose fraction by methods commonlyused in the sugar industry, such as by crystallization or as a syrup, oras liquid sugar subsequent to purification. Betaine is recovered fromthe second betaine fraction by crystallization, for example, asdescribed in U.S. Pat. No. 4,359,430.

To optimize the sucrose and betaine yields and purity, the pH of thefeed solution also may be adjusted. It is generally adjusted prior tothe second fractionation to the range 6.5-12, and preferably between9.5-11.5.

The following examples illustrate the method of the invention in thecontext of fractionating beet molasses to recover sucrose and betaine.It is not intended that the invention be limited by this description ofthe preferred embodiments.

EXAMPLE 1

Sequential SMB process; separation of sucrose and betaine from molasseswithout further separation of betaine fraction (reference example)

A chromatographic apparatus as schematically shown in FIG. 1 wasemployed. The apparatus comprised three columns 1-3 connected in series,fluid conduits 4-7 connecting the columns, a molasses container 8, awater/eluant container 9, a molasses feed conduit 10, an eluant feedconduit 11, a recycle pump 12, a molasses feed pump 13, an eluant feedpump 14:, heat exchangers 15-17, product fraction withdrawal conduits 6,18-20, 48 and 49 and valves 21-47.

The columns were packed with a strong cation exchanger resin known inthe trade as Finex CS 11 GC™, manufactured by Finex Oy. The resin had apolystyrene/divinylbenzene backbone and was activated with sulphonicacid groups; the mean bead size (in Na+ form) was about 0.38 mm. Theresin had a DVB content of 5.5%. Prior to the test, the resin wasregenerated to sodium form; during the fractionation it was equilibratedby cations from the feed solution.

Test conditions: Diameter of columns  0.2 m Total height of resin bed10.5 m Temperature 80° C.

The feed solution was beet molasses wherefrom calcium was precipitatedby adding sodium carbonate (pH about 9); the calcium carbonateprecipitate was removed by filtration.

Fractionation was performed using the following seven-step sequence:

Step 1: Feed solution 10 was introduced (feeding phase) into column 1through valve 22 at a flow rate of 80 l/hr., and a residue fraction waseluted from the downstream end of same column 1 through conduit 48.Simultaneously, eluant 11 was supplied (eluting phase) to column 2through valve 26 at a flow rate of 25 l/hr., and a sucrose fraction waseluted from column 3 through conduit 6.

Step 2: The liquid in the columns was recycled (recycling phase) in theloop formed by all columns at a rate 120 l/hr.

Step 3: Eluant 11 was introduced into column 1 through valve 23 at arate of 120 l/hr. and, simultaneously, a betaine fraction was elutedfrom column 3 through conduit 6.

Step 4: Eluant 11 was introduced (eluting phase) into column 1 throughvalve 23 at a flow rate of 120 l/hr., and a second residue fraction waseluted from the downstream end of column 2 through conduit 49.Simultaneously, eluant was supplied (eluting phase) to column 3 throughvalve 29 at a flow rate of 55 l/hr., and a second betaine fraction waseluted from the downstream end of the same column through conduit 6.

Step 5: Same as step 2.

Step 6: Eluant 11 was introduced into column 1 through valve 23 at aflow rate of 120 l/hr., and a third residue fraction was eluted from thedownstream end of column 3 through conduit 6.

Step 7: Same as step 2.

After the sequence was carried out to completion, the process controlprogram returned to step 1. By repeating this sequence five to seventimes, the system was equilibrated. The method proceeded in a state ofequilibrium, and the process of the separation process was monitoredwith a density meter, a meter for optical activity, a conductivitymeter, and the separation was controlled by a microprocessor wherebyprecisely defined volumes and flow rates of feeds, recycled liquid andproduct fractions were controlled employing quantity/volume measuringmeans, valves and pumps.

In this method, a sucrose fraction from column 3, two betaine fractionsfrom column 3, and one residue fraction from each column were withdrawn.The betaine fractions were combined, as were the residue fractions.

Analyses of the feed solution and the product fractions withdrawn duringone sequence after an equilibrium was reached are presented in Table 1,where the percentages of the different components are given as percentby weight dry solids basis.

TABLE 1 Dry solids Sucrose Betaine g/100 g % % Feed solution 46.5 58.15.2 Sucrose fraction 25.8 92.1 0.8 Betaine fraction 4.2 18.1 55.6(combined) Residue fraction 5.0 12.7 4.5 (combined)

The sucrose yield into the sucrose fraction was 90.1% and the betaineyield into the combined betaine fraction 58.7%.

EXAMPLE 2

Sequential SMB process; separation of sucrose and betaine from molasses,further separation of betaine fraction.

The apparatus and test conditions described in Example 1 were employed.The procedure was also similar to that of Example 1, except that thefraction volumes were adjusted. The adjustment caused a higher purity,but lower yield, for sucrose and a lower purity, but higher yield, forbetaine than obtained in the first fractionation in Example 1.Subsequent to evaporation, the resulting betaine fraction was subjectedto re-fractionation by a similar sequential SMB process with differentconditions. The sucrose fraction obtained from the second fractionationwas combined with the sucrose fraction from the first fractionation, andthe residue fractions were likewise combined.

Analyses of the feed solutions and the product fractions withdrawnduring one sequence after an equilibrium was reached are presented inTable 2, where the percentages of the different components are given aspercent by weight dry solids basis.

TABLE 2 Dry solids Sucrose Betaine g/100 g % % First fractionation Feedsolution 46.5 58.1 5.2 Sucrose fraction 25.5 92.6 0.4 Betaine fraction3.3 21.3 43.9 Residue fraction 4.8 11.7 0.9 Second fractionation Feedsolution 55.0 21.3 43.9 Sucrose fraction 14.0 82.6 1.0 Betaine fraction8.3 1.1 85.2 Residue fraction 4.1 11.2 2.2 Combined product fractionsSucrose fraction 24.7 92.2 0.4 Residue fraction 4.7 11.7 1.0

The sucrose yield from the first fractionation was 89.4% and the betaineyield was 89.9%. The total sucrose yield, calculated from the combinedsucrose fraction, was 92.6% and the total betaine yield, calculated fromthe betaine fraction obtained from the second fractionation, was 88.2%The second fractionation afforded remarkable improvement of the sucroseyield and betaine purity. In addition, the betaine yield improvedsignificantly as compared with Example 1.

EXAMPLE 3

The method described in Example 2 was essentially followed, but theeffect of the pH of the feed solution for the second fractionation(which solution had been obtained from the betaine fraction from thefirst fractionation) was studied, performing the second fractionation insuch a way that (a) the pH of the feed solution was not adjusted, and,hence, the pH was 10.2, (b) the pH of the feed solution was adjustedwith hydrochloric acid to 9.5, and (c) the pH of the feed solution wasadjusted with NaOH to 11.2.

Analyses of the feed solution for the second fractionation (i.e. furtherseparation of the betaine fraction) and the product fractions withdrawnduring one sequence after an equilibrium was reached are presented inTable 3, where the percentages of the different components are given aspercent by weight dry solids basis.

TABLE 3 Dry solids Sucrose Betaine g/100 g % % Feed solution 43.0 32.524.8 (a) pH 10.2 Sucrose fraction 16.6 84.6 0.1 Betaine fraction 6.2 0.489.3 (b) pH 9.5 Sucrose fraction 17.9 81.1 0.1 Betaine fraction 6.2 0.488.0 (c) pH 11.2 Sucrose fraction 15.4 82.5 0.1 Betaine fraction 6.1 0.190.4

The yields from the second fractionation in the above cases (a), (b) and(c) were as follows:

(a) sucrose 57.3%, betaine 95.4%

(b) sucrose 59.6%, betaine 96.8%

(c) sucrose 51.9%, betaine 96.8%.

As will be seen from the results, the pH of the feed solution affectsthe purity and yield of sucrose and betaine. The pH may be adjusted inaccordance with the economical optimum.

EXAMPLE 4

Continuous SMB process; separation of sucrose and by-product fractionfrom molasses (reference example).

The test apparatus comprised 14 columns connected in series, each havinga diameter of 0.2 m and each containing a packed bed having a height of0.85 m. FIG. 2 shows a schematic diagram of the test apparatus.

The columns were packed with a polystyrene-based cross-linked (5.5% DVB)strong cation exchanger having a mean bead size of 0.32 mm. The packingmaterial was equilibrated with feed solution and was predominantly inpotassium and sodium form.

Water, as eluant, was introduced into the column system through conduit50 at a flow rate of 83.5 l/hr. Feed solution was introduced throughconduit 51 to each column through feed valves 52-65 at a flow rate of13.5 l/hr. for 150 seconds. The feed conduits were rinsed with eluant(30 s, 13.5 l/hr.) subsequent to the introduction of the feed solution.The flow rate of the product fraction through valves 66-79 was adjustedto 21 l/hr., which produced a by-product flow rate of 76 l/hr. Theby-product fraction was withdrawn through spring-biased valves 80-93securing the desired pressure for the system. An average recycle rate of300 l/hr. was maintained. In practice, this rate varies according to thechange of the relative positions of the feed and product valves alongthe recirculation loop. The points of introduction of the feed solutionand eluant and the withdrawal points of the product fractions wereshifted downstream one column each successive step at intervals of 180seconds.

Initially, the system was filled with a higher feed flow rate and lowereluant flow rate. Once the system was filled, the flow rate setpointsstated above were used to run the system until an equilibrium had beenestablished.

Samples were taken at two-minute intervals via a sampling valve placedin the recirculation loop. The concentration gradient shown in FIG. 3was drawn on the basis of an analysis of the samples. In addition, thefeed solution and the product and by-product fractions were analyzed.The results are shown in Table 4, where the percentages of the differentcomponents are given as percent by weight on a dry solids basis.

TABLE 4 Product By-product Feed Solution fraction fraction Dry solids65.0 25.3 4.9 content, g/100 g Sucrose, % 60.4 87.2 19.0 Betaine, % 5.54.5 7.0 Raffinose, % 2.1 0.9 4.0 Others, % 32.0 7.4 70.0 Flow rate,l/hr. 13.5 21.0 76.0 Sucrose yield into sucrose fraction 87.6

EXAMPLE 5

Continuous SMB process for separation of sucrose and betaine frommolasses and batch method for further separation of betaine fraction

Molasses was fractionated by the continuous SMB method, wherein thefourteen-column system of Example 4 was modified in such a way that itwas possible to withdraw three product fractions: sucrose, betaine, andby-product fractions. FIG. 4 shows a schematic diagram of the testapparatus. The flow rate of the sucrose fraction was adjusted to 21l/hr. and the flow rate of the betaine fraction to 18 l/hr. The feedrate of the eluant through conduit 94 was 90.5 l/hr., and the feed flowrate through conduit 95 was 13.5 l/hr. Hence, the flow rate of theby-product fraction through conduit 96 was 65 l/hr.

The betaine fraction was concentrated to a dry solids content of 55% andfed to a separation system comprising two columns connected in series.The columns had a diameter of 0.2 m, and the packed bed in each columnhad a height of 0.85 m. The packing material was the same as in Example4.

The betaine fraction was further fractionated using a batch process,supplying 2.6 liters of feed solution (55% by weight on a dry solidsbasis) to the upstream end of the first column. The feed was repeatedlyintroduced at intervals of 60 minutes. Elution was performed at a flowrate of 30 l/hr. The following fractions were withdrawn from the bottomof the column:

Fraction 1: By-product 8.6 liters Fraction 2: Recycle fraction 2 liters(introduced into the column prior to the actual feed) Fraction 3:Product solution 2.6 liters Fraction 4: Recycle fraction 1.4 liters(introduced into the column subsequent to the actual feed) Fraction 5:Betaine fraction 5.0 liters Fraction 6: Blution recycling 10 liters

In the test example, the betaine separation had more capacity than thesingle SMB-column system with respect to betaine fraction produced.

The filling and equilibration of the column system, sampling, andanalyzing of the samples were performed as above. The concentrationgradient from the first continuous SMB separation is shown in FIG. 5.The results are shown in Table 5, where the percentages of the differentcomponents are given as percent by weight on a dry solids basis.

TABLE 5 Dry solids content Sucrose Betaine Raffinose Others Flow rateg/100 g % % % % l/hr. Fraction of molasses, continuous SMB Feed solution65.0 60.4 5.5 2.1 32.0 13.5 Sucrose fraction I 25.2 87.6 4.5 0.9 7.021.0 Betaine fraction I 3.5 45.2 31.1 0.4 23.3 18.0 By-product fractionI 4.9 13.7 2.3 4.6 79.4 65.0 Sucrose yield into sucrose fraction 87.6%Betaine yield into betaine fraction 37.0% Fractionation of betainefraction, batch method Feed solution 55.0 45.2 31.1 0.4 23.3 Sucrosefraction II 22.8 92.6 2.2 0.2 5.0 Betaine fraction II 10.3 5.4 88.3 0.06.3 By-product fraction II 4.5 18.0 3.2 1.2 77.6 Sucrose yield intosucrose fraction 86.2% Betaine yield into betaine fraction 94.5%Combined sucrose and by-product fractions Sucrose fraction I + II 25.187.8 4.4 0.9 6.9 Betaine fraction II 10.3 5.4 88.3 0.0 6.3 By-productfraction I + II 4.8 13.9 2.3 4.5 79.3 Sucrose yield into sucrosefraction 91.8% Betaine yield into betaine fraction 35.0%

As can be seen from the results, the yield of sucrose increased from87.6% to 91.8% and the purity of sucrose increased from 87.2% to 87.8%.With this modification, betaine was recovered with a yield of about 350and a purity of 88.3% The low betaine yield is a result of thecontinuous SMB method in which the feed flow was uninterrupted, and thusa considerable portion of the betaine was lost in the sucrose fraction.By increasing the eluant flow rate and increasing the flow rate of thebetaine fraction proportionately, the betaine yield is predicted toincrease up to about 50-60%.

EXAMPLE 6

Sequential SMB method for separation of sucrose and betaine frommolasses and further separation of betaine fraction.

The continuous SMB process disclosed in Example 4 was converted into asequential method in such a way that the columns of Example 4, referredto as sectional packed beds herein, were interconnected in sequence toform a four-column system in which two columns were formed by sectionalpacked beds 1-3 and 4-6, and two columns by sectional packed beds 7-10and 11-14. Thus, the system comprised two columns having a totalsectional packed bed height of 2.55 m each, and two columns having atotal sectional packed bed height of 3.4 m each. FIG. 6 shows aschematic diagram of the apparatus.

Fractionation was performed sequentially by the following eight-stepsequence:

Step 1: 15 liters of feed solution was introduced into sectional packedbed 1 at a flow rate of 75 l/hr., and a by-product fraction waswithdrawn from sectional packed bed 10. 20 liters of eluant: wasintroduced into sectional packed bed 11 at a flow rate of 100 l/hr., anda sucrose fraction was withdrawn from sectional packed bed 14.

Step 2: 8 liters of liquid was recycled at a flow rate of 100 l/hr. inthe loop formed by all columns.

Step 3: 12 liters of eluant was introduced into sectional packed bed 1at a flow rate of 120 l/hr. and a by-product fraction was withdrawn fromcolumn sectional packed bed 3. Simultaneously, 12 liters of eluant wassupplied to sectional packed bed 4 at a flow rate of 120 l/hr., and abetaine fraction was withdrawn from sectional packed bed 14.

Step 4: 14 liters of eluant was introduced into sectional packed bed 1at a flow rate of 120 l/hr., and a betaine fraction was withdrawn fromsectional packed bed 14.

Step 5: 8 liters was recycled at a flow rate of 100 l/hr. in the loopformed by all columns.

Step 6: 10 liters of eluant was introduced into sectional packed bed 1at a flow rate of 100 l/hr., and a by-product fraction was withdrawnfrom sectional packed bed 14.

Step 7: 4 liters of eluant was introduced into sectional packed bed 1 ata flow rate of 120 l/hr., and a by-product fraction was withdrawn fromsectional packing material bed 14.

Step 8: 12 liters of eluant was introduced into sectional packed bed 7.The profile was shifted by way of recirculation to sectional packed bed1, and a by-product fraction was withdrawn from sectional packed bed 6.

The betaine fraction was concentrated to a dry solids content of 55% andintroduced into a separation system comprising three columns. FIG. 7shows a schematic diagram of the apparatus. The columns had a diameterof 0.2 m, and the packed bed in each column had a height of 0.85 m. Thepacking material was the same as in Example 4.

Fractionation was performed sequentially by the following eight-stepsequence:

Step 1: 2 liters of feed solution was introduced into column 1 at a flowrate of 60 l/hr., and a by-product fraction was withdrawn from column 2.2.7 liters of eluant was supplied to column 3 at a flow rate of 80l/hr., and sucrose fraction was withdrawn from column 3.

Step 2: 1.5 liters of feed solution was supplied to column 1 at a flowrate of 60 l/hr., and a sucrose fraction was withdrawn from column 3.

Step 3: 1.5 liters was recycled at a flow rate of 60 l/hr. in the loopformed by all columns.

Step 4: 3 liters of eluant was introduced into column 1 at a flow rateof 60 l/hr., and a betaine fraction was withdrawn from column 3.

Step 5: 1.8 liters of eluant was introduced into column 1 at a flow rateof 54 l/hr., and a by-product fraction was withdrawn from column 1.Simultaneously, 4 liters of eluant was supplied to column 2 at a flowrate of 120 l/hr., and a betaine fraction was withdrawn from column 3.

Step 6: 3 liters was recycled at a flow rate 60 l/hr. in the loop formedby all columns.

Step 7: 1.5 liters of eluant was introduced into column 1 at a flow rateof 60 l/hr., and a by-product fraction was withdrawn from column 3.

Step 8: 3 liters was recycled at a flow rate of 60 l/hr. in the loopformed by all columns.

With this procedure, the betaine separation has double the capacity ofthe first separation stage with respect to the amount of the betainefraction produced. Thus, it was not attempted in this test to optimizethe sequence with respect to capacity and energy consumption, but goodyields and purities were pursued. This resulted in low fractionconcentrations. It is obvious to those skilled in the art that, on anindustrial scale, optimization is realized on an economic basis, thusthe optimum values may vary from the values disclosed herein.

The filling and equilibration of the column system, sampling, andanalyses of the samples were performed similarly as in Example 4. Theconcentration gradient from the output of sectional packed bed 14 in thefirst continuous SMB separation is shown in FIG. 8. The results areshown in Table 6, where the percentages of the different components aregiven as percent by weight on a dry solids basis.

TABLE 6 Dry solids Raffi- content Sucrose Betaine nose Others g/100 g %% % l/hr. Fraction of molasses, sequential SMB Feed solution 55.0 60.45.5 2.1 32.0 Sucrose fraction I 24.3 92.3 0.9 1.2 5.6 Betaine fraction I3.9 44.9 45.5 0.7 8.9 By-product fraction I 5.9 14.1 0.6 4.0 81.3Sucrose yield into sucrose fraction 84.1% Betaine yield into betainefraction 87.3% Fractionation of betaine fraction, sequential SMB Feedsolution 55.0 44.9 45.5 0.7 8.9 Sucrose fraction II 22.5 91.7 5.3 0.52.5 Betaine fraction II 16.0 7.4 88.9 0.0 3.7 By-product fraction II 3.025.3 1.0 5.5 68.2 Sucrose yield into sucrose fraction 87.0% Betaineyield into betaine fraction 94.8% Combined sucrose and by-productfractions Sucrose fraction I + II 24.2 92.3 1.2 1.1 5.4 Betaine fractionII 16.0 7.4 88.9 0.0 3.7 By-product fraction I + II 5.7 14.4 0.6 4.081.0 Sucrose yield into sucrose fraction 91.0% Betaine yield intobetaine fraction 82.8%

As can be seen from FIG. 8, significantly better separation of betainefrom sucrose is achieved compared to the fully continuous method ofExample 5. Table 6 shows that with substantially similar column loads,the sequential method also yields a considerably higher purity of 92.3%,for the sucrose fraction than the 87.2-87.8% for the fully continuousmethod. Double separation permits the first fractionation to beperformed with a relatively low sucrose yield, e.g., 84.1%, thusrealizing the need for a high separation capacity and low evaporation.Double separation increases the sucrose yield to 91.0%. The betaineyield may easily be increased to 82.8%, and with a higher eluantquantity and column capacity, the betaine yield may exceed 90%.

We claim:
 1. A method for processing a beet-derived sucrose-containingmaterial, comprising the steps of: fractionating a beet-derivedsucrose-containing material comprising a dissolved component in a firstloop comprising a first fractionator into at least two fractions, thefirst of said fractions comprising a greater percentage of saiddissolved component on a dry substance basis than any other fractionfrom said first fractionator, and said dissolved component selected fromthe group consisting of betaine, inositol, raffinose, galactinol,serine, and amino acid; fractionating a stream comprising said firstfraction in a second loop comprising a second fractionator into afraction comprising sucrose and another fraction comprising a greaterpercentage of said dissolved component on a dry substance basis thansaid first fraction; and said fractionators comprising a series ofcolumns, beds, or parts thereof, said second fractionator having atleast one column, bed, or part thereof, separate and distinct from saidfirst fractionator; said fractionating in said first fractionatorselected from the group consisting of a continuous chromatographicsimulated moving bed process and a sequential chromatographic moving bedprocess; said fractionating in said second fractionator selected fromthe group consisting of a batch separation process, a continuoussimulated chromatographic moving bed process, and a sequential simulatedchromatographic moving bed process; and wherein said second fraction issubjected to evaporation prior to being fractionated in said secondloop.
 2. The method of claim 1 wherein said beet-derived sucrosecontaining material comprises molasses.
 3. The method of claim 1 whereinsaid dissolved component is betaine.
 4. The method of claim 1 whereinsaid dissolved component is raffinose.
 5. A method for producingfractions comprising sucrose and a dissolved component from abeet-derived sucrose-containing, material comprising the steps of:fractionating a beet-derived sucrose-containing material in a first loopby a chromatographic simulated moving bed process to produce at least afirst fraction and a second fraction, said second fraction comprisingsucrose and a dissolved component selected from the group consisting ofbetaine, inositol, raffinose, galactinol, serine and amino acid;fractionating a stream comprising said second fraction in a second loopby chromatographic fractionation to produce at least a third fractionand a fourth fraction, said third fraction comprising sucrose, saidfourth fraction comprising sucrose and said dissolved component, saidthird fraction comprising a higher percentage concentration by weightsucrose on a dry substance basis than said second and fourth fractions,said fourth fraction comprising a higher percentage concentration byweight on a dry substance basis of said dissolved component than saidsecond fraction, and said second loop being different than said firstloop; and wherein said second fraction is subjected to evaporation priorto being fractionated in said second loop.
 6. The method of claim 5wherein said first fraction is selected from the group consisting of asucrose fraction, a by-product fraction, and a residue fraction.
 7. Themethod of claim 5 wherein the second fraction is combined with the firstfraction to produce said stream comprising said second fraction in saidsecond loop.
 8. The method of claim 5 wherein said first fractioncomprises the highest percentage of raffinose on a dry substance basis.9. The method of claim 5 wherein said dissolved component is betaine.10. The method of claim 9 wherein said second fraction comprises atleast about 30% to about 45% by weight betaine and said fourth fractioncomprises at least about 85% to about 90% by weight betaine.
 11. Themethod of claim 5 wherein the simulated moving bed process in said firstloop is selected from the group consisting of a continuous simulatedmoving bed process and a sequential simulated moving bed process. 12.The method of claim 5 wherein the chromatographic fractionation in saidsecond loop comprises a batch method.
 13. The method of claim 5 whereinthe chromatographic fractionation in said second loop is selected fromthe group consisting of a continuous simulated moving bed process and asequential simulated moving bed process.
 14. The method of claim 9wherein each loop comprises a series of columns.
 15. The method of claim5 wherein the fractionation in said first and second loops is performedwith a cation exchanger and each of said loops comprises a separatefractionator.
 16. The method of claim 5 wherein the dry solids contentof the stream fed to the second loop for fractionation is adjusted tothe range of about 20-80g/100 g.
 17. The method of claim 5 wherein thepH of the stream fed to the second loop for fractionation is adjusted tothe range of about 6.5-12.
 18. The method of claim 5 wherein saiddissolved component is betaine.
 19. The method of claim 5 wherein saiddissolved component is raffinose.
 20. The method of claim 5 wherein:said second fraction is enriched with said dissolved component; saidthird fraction is enriched with sucrose; and said fourth fraction isenriched with said dissolved component.
 21. The method of claim 5including adjusting volumes of said first fraction and said secondfraction.
 22. The method of claim 5 wherein said second fraction has adry solids content which is adjusted prior to fractionating said streamin said second loop.
 23. The method of claim 5 wherein said secondfraction is concentrated prior to being fractionated in said secondloop.
 24. A method for producing fractions comprising sucrose and adissolved component from a beet-derived sucrose-containing materialcomprising the steps of: fractionating a beet-derived sucrose-containingmaterial in a first loop by a chromatographic simulated moving bedprocess to produce at least a first fraction and a second fraction, saidsecond fraction comprising sucrose and a dissolved component selectedfrom the group consisting of betaine, inositol, raffinose, galactinol,serine and amino acid; fractionating a stream comprising said secondfraction in a second loop by chromatographic fractionation to produce atleast a third fraction and a fourth fraction, said third fractioncomprising sucrose, said fourth fraction comprising sucrose and saiddissolved component, said third fraction comprising a higher percentageconcentration by weight sucrose on a dry substance basis than saidsecond and fourth fractions, said fourth fraction comprising a higherpercentage concentration by weight on a dry substance basis of saiddissolved component than said second fraction, and said second loopbeing different than said first loop; and wherein part of one of saidfractions is recycled to a solution comprising said beet-derivedsucrose-containing material for fractionating in said first loop. 25.The method of claim 24 wherein said dissolved component is raffinose.26. The method of claim 24 wherein said first fraction is selected fromthe group consisting of a sucrose fraction, a by-product fraction and aresidue fraction.
 27. The method of claim 24 therein the second fractionis combined with the first fraction to produce said stream comprisingsaid second fraction in said second loop.
 28. The method of claim 24wherein said first fraction comprises the highest percentage ofraffinose on a dry substance basis.
 29. The method of claim 24 whereinsaid dissolved component is betaine.
 30. The method of claim 20 whereinsaid second fraction comprises at least about 30% to about 45% by weightbetaine and said fourth fraction comprises at least about 85% to about90% by weight betaine.
 31. The method of claim 24 wherein the simulatedmoving bed process in said first loop is selected from the groupconsisting of a continuous simulated moving bed process and a sequentialsimulated moving bed process.
 32. The method of claim 24 wherein thechromatographic fractionation in said second loop comprises a batchmethod.
 33. The method of claim 24 wherein the chromatographicfractionation in said second loop is selected from the group consistingof a continuous simulated moving bed process and a sequential simulatedmoving bed process.
 34. The method of claim 24 wherein each loopcomprises a series of columns.
 35. The method of claim 24 wherein thefractionation in said first and second loops is performed with a cationexchanger and each of said loops comprises a separate fractionator. 36.The method of claim 24 wherein the dry solids content of the stream fedto the second loop for fractionation is adjusted to the range of about20-80g/100 g.
 37. The method of claim 24 wherein the pH of the streamfed to the second loop for fractionation is adjusted to the range ofabout 6.5-12.
 38. The method of claim 24 wherein said dissolvedcomponent is betaine.
 39. The method of claim 24 wherein said dissolvedcomponent is raffinose.
 40. The method of claim 24 wherein: said secondfraction is enriched with said dissolved component; said third fractionis enriched with sucrose; and said fourth fraction is enriched with saiddissolved component.
 41. The method of 24 including adjusting volumes ofsaid first fraction and said second fraction.
 42. The method of claim 24wherein said second fraction has a dry solids content which is adjustedprior to fractionating said stream in said second loop.
 43. The methodof claim 24 wherein said second fraction is concentrated prior to beingfractionated in said second loop.
 44. A method for processing abeet-derived sucrose-containing material, comprising the steps of:fractionating a beet-derived sucrose-containing material comprising adissolved component in a first loop comprising a first fractionator intoat least two fractions, the first of said fractions comprising a greaterpercentage of said dissolved component on a dry substance basis than anyother fraction from said first fractionator, and said dissolvedcomponent selected from the group consisting of betaine, inositol,raffinose, galactinol, serine, and amino acid; fractionating a streamcomprising said first fraction in a second loop comprising a secondfractionator into a fraction comprising sucrose and another fractioncomprising a greater percentage of said dissolved component on a drysubstance basis than said first fraction; said fractionator comprising aseries of columns, beds, or parts thereof, said second fractionatorhaving at least one column, bed, or part thereof, separate and distinctfrom said first fractionator; said fractionating in said firstfractionator selected from the group consisting of a continuouschromatographic simulated moving bed process and a sequentialchromatographic moving bed process; said fractionating in said secondfractionator selected from the group consisting of a batch separationprocess, a continuous simulated chromatographic moving bed process, anda sequential simulated chromatographic moving bed process; and whereinpart of one of said fractions is recycled to a solution comprising saidbeet-derived sucrose-containing material for fractionating in said firstloop.
 45. The method of claim 24 wherein said beet-derived sucrosecontaining material comprises molasses.
 46. The method of claim 41wherein said dissolved component is betaine.
 47. The method of claim 41wherein said dissolved component is raffinose.